Sulfonated polyether ether ketone (PEEK-WC)/phosphotungstic acid composite: Preparation and characterization of the fuel cell membranes
Ji Shan, Guntars Vaivars, Hongze Luo, Rushanah Mohamed, and Vladimir Linkov
Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville, 7535, Cape Town, Western Cape, South Africa
Abstract: Sulfonated poly(oxa-p-phenylene-3,3-phthalido-p-phenylene-oxa-p-phenylene-oxy-phenylene) (PEEK-WC) membranes with various degrees of sulfonation (DS) were prepared, and their electrochemical and thermal properties were studied. Composites were formed by adding the hydrated phosphotungstic acid (PWA). The membrane (DS = 0.96, PWA = 50 %) conductivity was increased to 3.5 x 10-2 S cm-1 at room temperature and 6.0 x 10-2 S cm-1 at 80 °C. The composite membrane with a low amount of PWA embedded, showed lower methanol crossover in comparison to Nafion®. The addition of PWA increased the water retention of the composite membrane.
Keywords: membranes; nanocomposites; proton conductivity; sulfonated PEEK-WC;hydrated phosphotungstic acid; direct methanol fuel cells.
*Paper based on a presentation at the 3rd IUPAC Workshop on New Directions in Chemistry - Workshop on Nanostructured Advanced Materials (WAM III), Stellenbosch, South Africa, 5-9 September 2005. Other presentations are published in this issue, pp. 1619-1801.